Characteristic and outcomes of patients with pathologic complete response after preoperative treatment in borderline and locally advanced pancreatic adenocarcinoma: An AGEO multicentric retrospective cohort.

ABSTRACT

INTRODUCTION: Following publication of improved patients' outcome using first line FOLFIRINOX for metastatic pancreatic adenocarcinoma, many physicians now prescribe it as neo-adjuvant or induction treatment for borderline and locally advanced pancreatic cancer. A pathologic complete response, rarely seen with previous preoperative regimens, is sometimes observed in these patients. The aim of this study was to assess long-term outcomes of patients presenting pathologic complete response after preoperative FOLFIRINOX usually followed by chemo-radiation therapy for non-metastatic pancreatic adenocarcinoma. MATERIAL AND METHODS: We retrospectively identified all resected patients with pancreatic cancer presenting pathologic complete response after FOLFIRINOX in 9 French centers from the AGEO group between November 2010 and May 2017. RESULTS: 29 patients were enrolled, 14 had borderline, 14 locally advanced and 1 oligo-metastatic pancreatic cancer. M/F ratio was 1.2 and the mean age was 57 years. All patients were treated with FOLFIRINOX (n = 29), de-escalated to gemcitabine (n = 1) and FOLFIRI (n = 2), and 24 (83 %) received radiation therapy after chemotherapy. Objective response rate to preoperative chemotherapy was 66% (RECIST V1.1). Only 8 patients received postoperative chemotherapy. After a median follow-up of 34 months from surgery, the median overall survival was not reached and the median disease free survival was 48 months. The 1-year and 2-year survival rates were 100% for OS and 96% and 72 % for DFS from surgery, 8 of the 9 observed recurrences were distant metastases. CONCLUSIONS: The promising 1 and 2-year overall survival and disease free survival rates suggest that pathologic complete response is a major prognostic factor in resected pancreatic cancer following preoperative chemo-radiotherapy. A longer follow-up and prospective series are now necessary to confirm these encouraging results and to potentially validate pathologic complete response as a relevant surrogate marker of preoperative treatment efficacy.